We obtained previously considerable evidence indicating the expression of AMPA/kainater receptors not only by neurons but also Muller cells. Cytosolic calcium transients following an agonist administration to Muller cells cultured from adult rabbit retinas were examined with spectrofluorometry using fura-2 AM.Calcium transients occurred more in number for neurotoxic kainate exposed that control cells, suggesting the AMPA/kainate receptors develop be novo in pathological state. Using the above methods to detect calcium transients, we found approximately 50% of neurons cultured from neonatal rat retinas responded to muscarine at 50 muM , but 50 muM was requisite for the formation of calcium transients in 50% of cultured Muller cells. The muscarine inducement of calcium transients was blocked by atropine. The agonist of M1, McN-A-343 eliciteed the most significant calcium transients both in neurons and Muller cells. Thus, Muller cells appeared to possess the less sensitive muscarinic receptor including at least M1. P_1-/P_2-purinergic receptor agonists including A2 and P2y induced calcium transients in cultured Muller cells. Muller cells are thus shown guite likely to possess the P_1-/P_2-purinergic receptors. A new excitotoxic amino acid, dysiherbaine is also studied and it induced calcium transients in Muller cells but appeared not to be mediated by known AMPA/Kainate receptors, since the receptor antagonists (CNQX and DNQX) to be mediated by kmown AMPM/Kainate receptors, since the receptor antagonists (CNQX and DNQX) could not block the transients.一方、神経伝達物質として網膜に存在しそいるほかの神経伝達物質受容体のうち、アセチルコリン受容体、アデノシン/プリン受容体についても、受容体アゴニスト、アンタゴニストを利用して、同様に薬理学的実験を進めた。その結果、培養ミュラー細胞からは、アセチルコリン受容体のうちニコチン受容体の存在はつかめなかったが、ムスカリン受容体、とりわけM1受容体の存在が明らかになった。またP1/P2プリン受容体の存在も確認され、イオンチャンネル受容体であるA1、A2、P2x、および代謝制御型受容体のP2yはいずれも存在していることが強く示唆され、特にA2、P2yでは強い応答が多くの細胞で得られた。